1. Field of the Invention
The present invention relates to band saws utilized in cutting sheet metal and the like. Specifically, the present invention relates to a machine having dual band saws powered by a single variable speed motor.
2. Description of the Prior Art
Band saws for cutting wood, metal, and other suitable objects appear in the patent record since the early 1880's. However, very few dual band saws have been patented since that time. Furthermore, very few band saws provide a large enough throat area so that the material being cut does not have to constantly be removed and repositioned. Band saws with two separate work stations and utilizing two independent cutting bands powered by a single variable speed power source were not seen in the prior art. These features, as well as others related to band saws, have been patented individually in prior patents. However, the combination of these features into a single dual band saw has not been accomplished prior to the present invention. The following patents present band saws and band saw apparatus that show some of the individual aspects and features mentioned above.
U.S. Pat. No. 357,681, issued on Feb. 15, 1887 to Joseph W. Maxwell, discloses a dual band saw for cutting an object, at a predetermined and variable angle, with respect to the vertical, to cut a piece of wood into a desired shape, wherein the shape may be curved, intricate, or otherwise irregular. Although, this band saw is seen as having two four wheeled band saw blades incorporated therein, the blades are configured to work on the same piece of material. Thus, the out-of-plane, essentially one-behind-the-other configuration of the blades is used to position the blades close enough so that they may work on the same object.
U.S. Pat. No. 4,146,945, issued on Apr. 3, 1979 to Septime R. Hotard, also discloses a band saw having a four wheel configuration. Hotard's band saw utilizes a horizontally positioned blade driving about four equal sized wheels in a square configuration, the band saw being capable of a vertical displacement of the entire blade assembly.
U.S. Pat. No. 4,333,370 issued on Jun. 8, 1982 to Ernst Th. Sack, discloses a band saw apparatus having three band guide rollers, or wheels, in an equilateral triangle configuration, for cutting large cast slabs. Although Sack's band saw utilizes a triangular shape similar to the right triangle configuration used in the present invention, it is unable to accommodate two simultaneous cutting operations. In addition, Sack's apparatus is to be used in series with a number of additional cutting machines to cut the same object.
Looking now at U.S. Pat. Nos. 4,624,167 issued on Nov. 25, 1986 to Joseph M. Stephanic, and 4,557,168, issued on Dec. 10, 1985 to Toru Tokiwa, examples of first manual adjustment of a variable speed motor and second electromagnetical detection of an element on a wheel are shown. Stephanic's patent discloses means for adjusting a variable speed motor from a remote location through a series of chain and shaft linkages. However, the present invention's utilization of a universal joint in the shaft linkages allows the motor to be displaced for tensioning of the drive belts without binding and jamming the linkages. Tokiwa's band saw utilizes magnets and magnetic detection means for determining the location and adjusting the band saw blade.
U.S. Pat. No. 4,893,533, issued on Jan. 16, 1990 to Gerald R. Harris, discloses a band saw capable of cutting a number of different objects at the same time. Harris' band saw, however, accomplishes this task by employing a plurality of parallel guides capable of holding small articles needing to be cut. Not only is this saw unable to accommodate two different craftsmen, the multiple objects being cut may not be moved independently with respect to one another during the cutting process.
Lastly, U.S. Pat. No. 919,566, issued on Apr. 27, 1909 to Hermann G. Dittbenner, and British Patent Specification 21,387, issued on September 19, 1912, disclose typical two wheeled single band, band saws.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.